1. Field of the Invention
The present invention relates to a filter-press type electrolytic cell for sea water to obtain sodium hypochlorite from the sea water without substantial formation of such deposits as calcium and magnesium components in the sea water, upon the surface of cathodes.
2. Description of the Prior Art
In the electrolytic cell for sea water, calcium carbonate and magnesium hydroxide which deposits on cathode surfaces leads to increase in operating cell voltage and decrease in current efficiency, and builds up thicknesses that impede or prevent electrolyte flow. Electrolysis is then intermittently interrupted, unless some procedures such as backwash, acidwash are taken to remove these deposits.
In many conventional electrolytic cells for sea water, with vertically disposed electrodes, the sea water enters to the cell below the electrodes. Since the sea water is in contact with the bottom edge of the electrodes, the deposits of magnesium and calcium components in the sea water are unavoidable.
In order to remove this disadvantage, a preventive of such deposits, by means of the round-bottomed electrodes or wedge-bottomed electrodes, is proposed by the Utility Model Application in Japan published under No.JP(U)79-143361(Jikkaisho 54-143361). Deposits of the components of sea water are considerably reduced by this method, but deposits should not be completely prevented if the content of hardness components in sea water is high or the operation runs for a long time.
On the other hand, the electrolytic cell with vertically mounted cell units, is publicly known by the Patent Application in Japan published under NO.JP(A) 83-171587 (Tokkaisho 58-171587). However, in this patent application no disclosure is given with regard to the deposits of metallic components of sea water nor the passage of electrolyte in the cell unit.